Converters used in steel production are typically supported in a trunnion ring that has first and second trunnions at opposite sides of the ring, whereby each trunnion is rotationally supported via a bearing arrangement. One of the trunnions is connected to a drive gear for tilting the trunnion ring and converter, to enable molten metal within the converter to be poured out. As is generally known, the trunnion at the driven side is supported by a locating bearing arrangement, while the trunnion at the non-driven side is supported by a non-locating bearing arrangement, which allows for expansions and contractions of the trunnion ring, relative to fixed supports. The bearing arrangement also needs to accommodate high radial loads and angular misalignments.
An example of such a non-locating bearing arrangement, or expansion bearing arrangement, is disclosed in U.S. Pat. No. 3,523,714. The arrangement comprises a double-row spherical roller bearing mounted in a housing. An inner ring of the bearing is fixedly mounted on the trunnion via a conical clamping sleeve, while an outer ring of the bearing is mounted to the housing via a slidable cylindrical sleeve that permits axial displacement of the bearing relative to the housing. The arrangement further comprises a protective bushing made of harder material than the slidable sleeve, which is mounted to the housing bore and provides the sliding surface for the slidable sleeve. Furthermore, anti-rotation means in the form of axial grooves and fitting keys are provided to prevent rotation of the slidable sleeve relative to the bushing, and circumferential grooves are provided to permit introduction of a lubricant.
In alternative solution, a toroidal roller bearing such as a CARBO bearing sold by SKF is used in the non-locating bearing arrangement. This type of bearing can withstand high radial loads, accommodate angular misalignments and has the advantage of permitting relative axial displacement between the inner and outer bearing rings. The use of a toroidal roller bearing therefore removes the need for an additional component such as a slidable sleeve. In some applications, however, the amount of relative axial displacement permitted by the toroidal roller bearing may be insufficient or may become insufficient over time, due to deformation of the trunnion ring.
There is still room for improvement.